521671638 has 16 divisors (see below), whose sum is σ = 1098256320. Its totient is φ = 164738376.

The previous prime is 521671637. The next prime is 521671663. The reversal of 521671638 is 836176125.

It is a junction number, because it is equal to n+sod(n) for n = 521671596 and 521671605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521671637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2287920 + ... + 2288147.

It is an arithmetic number, because the mean of its divisors is an integer number (68641020).

Almost surely, 2^521671638 is an apocalyptic number.

521671638 is an abundant number, since it is smaller than the sum of its proper divisors (576584682).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521671638 is a wasteful number, since it uses less digits than its factorization.

521671638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4576091.

The product of its digits is 60480, while the sum is 39.

The square root of 521671638 is about 22840.1321800028. The cubic root of 521671638 is about 805.0059220531.

The spelling of 521671638 in words is "five hundred twenty-one million, six hundred seventy-one thousand, six hundred thirty-eight".